Self-assembly of robust perylenediimide chromophores is used to produce an artificial light-harvesting antenna structure that in turn induces self-assembly of a functional special pair that undergoes ultrafast, quantitative charge separation. The structure consists of four 1,7-(3′,5′-di-tert-butylphenoxy)perylene-3,4:9,10-perylene-3,4:9,10-bis(carboximide) (PDI) molecules attached to a single 1,7-bis(pyrrolidin-1-yl)perylene-3,4:9,10-perylene-3,4:9,10-bis(carboximide) (5PDI) core, which self-assembles to form (5PDI-PDI4)2 in toluene. The system is characterized using both structural methods (NMR, SAXS, mass spectroscopy, and GPC) and photophysical methods (UV-vis, time-resolved fluorescence, and femtosecond transient absorption spectroscopy). Energy transfer from (PDI)2 to (5PDI)2 occurs with τ = 21 ps, followed by excited-state symmetry breaking of 1*(5PDI)2 to produce 5PDI•+-5PDI•- quantitatively with τ = 7 ps. The ion pair recombines with τ = 420 ps. Electron transfer occurs only in the dimeric system and does not occur in the disassembled monomer, thus mimicking both antenna and special pair function in photosynthesis.
ASJC Scopus subject areas
- Colloid and Surface Chemistry